This application claims priority to Korean Application No. 2001-77960, filed on Dec. 10, 2001 in the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference.
The present invention relates to a plasma display panel, and more particularly, to a plasma display panel using a helicon plasma source.
A plasma display panel (PDP) is a display device that utilizes emissions taking place in discharge cells to realize images. Among the different types of PDP configurations that have been developed, only the AC PDP has been produced on a commercial basis, with the surface discharge structure being far more prevalent than the columnar discharge structure. In the surface discharge AC PDP, an AC voltage is used to initiate a discharge between electrodes on opposing substrates, and another AC voltage is used to sustain a discharge between electrodes on the same substrate. Such an AC PDP will be described with reference to FIG. 7.
FIG. 7 shows a partial sectional view of a conventional AC PDP. As shown in the drawing, the conventional AC PDP includes upper substrate 2 and lower substrate 4 that are provided substantially in parallel and at a predetermined interval to thereby define an exterior of the PDP. Structures to realize images are provided on and between opposing faces of the upper and lower substrates 2 and 4.
In more detail, formed on the face of upper substrate 2 opposing lower substrate 4 are a plurality of discharge sustain electrodes 6 provided at predetermined intervals, dielectric layer 8 formed over discharge sustain electrodes 6, and protection layer 10 formed over dielectric layer 8. Formed on the face of lower substrate 4 opposing upper substrate 2 are a plurality of address electrodes 12 formed in a predetermined pattern such as a striped pattern (only one is shown in the drawing but it is to be assumed that more are formed over the entire surface of lower substrate 4), and a protection layer (not shown) that covers address electrodes, 12.
Further, barrier ribs 16 are provided between upper substrate 2 and lower substrate 4. Barrier ribs 16 define discharge-cells 14 and prevent crosstalk between adjacent cells (only one pair of barrier ribs defining a single discharge cell is shown in the drawing but it is to be assumed that this pattern continues over the entire surface of lower substrate 4). In addition, phosphor layer 18 is formed in discharge cells 14 covering surfaces of barrier ribs 16 within discharge cells 14 and covering the surface of lower substrate 4 opposing upper substrate 2 except at areas where address electrodes 12 are formed. Phosphor layer 18 is formed of R,G,B phosphors.
The upper substrate 2 is fused to lower substrate 4 using a frit (not shown), and a discharge gas such as an inert gas is injected into discharge cells 14 to thereby complete the PDP.
Using single discharge cell 14 of the partial AC PDP shown in FIG. 7 as an example, address voltage Va is applied between address electrode 12 and one of discharge sustain electrodes 6 to select the pixel to be driven. Further, discharge sustain voltage Vs is applied between the pair of discharge sustain electrodes 6. As a result, ultraviolet rays resulting from surface discharge are generated in discharge cell 14, and the ultraviolet rays illuminate phosphor layer 18. By repeating this process over the entire area of the PDP, specific images are realized.
In such a conventional PDP, discharge sustain electrodes 6, between which dielectric layer 8 is present, form a capacitance such that AC discharge occurs to realize images. Therefore, the PDP can be viewed as being a capacitively coupled PDP.
However, as is well known, the plasma density in such a capacitively coupled PDP is approximately 109xcx9c1010/cm3 such that when the PDP is structured to have a high discharge efficiency and high brightness characteristics, limitations are given to the PDP characteristics so that user requirements can not be satisfied.
The formation of such low density plasma is the basic limitation to having a capacitively coupled plasma source. That is, with the application of the discharge sustain voltage Vs to discharge sustain electrodes 6, electrons are accelerated by the generated electric field. At this time, the electrons typically have a statistical speed distribution. Among the electrons having this speed distribution, there is a limit to the number of electrons having a speed that is at or greater than the speed needed to ionize discharge gas atoms to generate plasma. Therefore, the plasma density is inherently low with the cell structure of the conventional capacitively coupled PDPs.
As such, a need exists for a plasma display panel having an increased plasma density in discharge cells during operation. The present invention provides a solution to meet such need.
In accordance with the present invention, a plasma display panel is provided that increases a plasma density in discharge cells during operation through the use of antenna and magnetic elements.
In one embodiment, the plasma display panel includes a first substrate and a second substrate mounted substantially in parallel with a predetermined gap therebetween. A plurality of address electrodes are formed on a surface of the first substrate opposing the second substrate. A first dielectric layer is formed on the first substrate covering the address electrodes. A plurality of barrier ribs is formed on the first dielectric layer at a predetermined height, the barrier ribs defining discharge cells between the first and second substrates. A phosphor layer is formed in the discharge cells. A plurality of discharge sustain electrodes is formed on a surface of the second substrate opposing the first substrate. A second dielectric layer is formed on the second substrate covering the discharge sustain electrodes. Discharge gas is injected into the discharge cells. Assemblies are provided to increase a plasma density in the discharge cells. The assemblies include an antenna element supported by the barrier ribs and a one or more magnetic elements provided on the first substrate.
Each of the assemblies, to increase the plasma density, includes a discharge antenna supported by the barrier ribs in one of the discharge cells. Drive power is applied to the discharge antenna from a source external to the plasma display panel. Magnet(s) are formed on the first substrate on the address electrode in the corresponding discharge cell or/and on an external surface of the first substrate opposite the surface of the first substrate opposing the second substrate and at a location corresponding to a position of the address electrode in the corresponding discharge cell.
In accordance with the present invention, the magnetic element may be a permanent magnet formed in a stripe pattern.
In another embodiment, the plasma display panel includes a first substrate and a second substrate mounted substantially in parallel with a predetermined gap therebetween. A plurality of magnets is formed on an interior surface or the interior surface and an exterior surface of the first substrate. A first dielectric layer is formed on the first substrate covering the magnets. A plurality of barrier ribs is formed on the first dielectric layer at a predetermined height, the barrier ribs defining discharge cells between the first and second substrates. A phosphor layer is formed in the discharge cells. A plurality of discharge sustain electrodes is formed on a surface of the second substrate opposing the first substrate, the discharge sustain electrodes being perpendicular to the magnets formed on the first substrate. A second dielectric layer is formed on the second substrate covering the discharge sustain electrodes. Discharge gas is injected into the discharge cells. Discharge antennas are supported by the barrier ribs in the discharge cells. Drive power is applied to the discharge antennas from a source external to the plasma display panel.